Adjustable struts

ABSTRACT

This invention relates to an adjustable telescopic strut with the inner member having a screw thread engaging a rotatable adjusting nut, in which the adjusting nut is readily disengageable from the screw thread to effect rapid adjustment of the strut.

it in States Patent Inventor Colin Wbeeloclt Clevedon, England Appl. No.876,935 IFiled Nov. 14, 1969 Patented fiept. 7, 1197! Assignee MillsScaffold Company Limited Landfill. England Priority Nov. 26, 1968 GreatBritain 55917/68 AWIUS'TILE STR U 4i (Zinims, 2 wing Figs.

ILLS. 0C] I354 S, 254/98 lint. Cl lll/ML E04g25/(1Z lFieitll of M248/354 S,

1 mm in Primary Examiner-William H. Schultz Attorney-A. Yates DowellACT: This invention relates to an adjustable telescopic strut with theinner member having a screw thread engaging a rotatable adjusting nut,in which the adjusting nut is readily disengageable from the screwthread ltO effect rapid adjustment of the strut.

PATENTEDSEP Han 3503.552

Inventor 6 Colin whee lock ADJUSTABLE STRUTS BACKGROUND OF THEINVENTION 1. Field of the Invention This invention relates to adjustablestruts of the kind herein called the kind specified, comprising innerand outer members of elongated form which telescope one within theother, the outer member being hollow to permit of the inner membertelescoping therein, the inner member having a peripheral screw threadon which works a nut which is adapted for loadtransmitting engagementwith one end of the outer member, the arrangement being such that byrotating the nut the overall length of the strut can be adjusted.

2. Description of the Prior Art Adjustable struts of the kind specifiedare often required to provide quite a wide range of adjustment so thatthe screw thread on the inner member may be of quite substantial lengthas much as 18 inches to 2 feet or even more and this means that the nuthas to be turned many times in adjusting the overall length of the strutfrom one extreme to the other, the extent to which it is necessary toturn the nut being increased by the fact that to enable the nut to beturned manually under load the helix angle of the screw thread must besmall, usually not more than about so that the number of screw threadsper unit length is greater than would be the case if a larger helixangle were possible.

The present invention has for its object the provision of an improvedarrangement which permits of the adjustment of the axial position of thenut being more quickly and easily effected.

SUMMARY OF THE INVENTION According to the present invention the nut isformed as two thread-carrying parts each extending around not more thanhalf of the circumference of the threaded part of the inner member, saidparts being connected hingedly together at positions spaced axiallybeyond one end of the nut thread, the arrangement being such that thenut parts can each be hinged out of threaded engagement with the screwthread on the inner member to permit of the nut being then displacedalong the length of the inner member without rotating the nut, each ofsaid parts of the nut having an outer member engaging face adapted toengage with the outer member at a position such in relation to the hingeposition that with the outer member in load-transmitting engagement withthe nut the parts thereof are held positively in threaded engagementwith the inner members.

Thus with the present invention rapid adjustment of the overall lengthof the strut can be effected while there is no risk of the nut beinginadvertently disengaged from the inner member while the strut is underload in that it would then be necessary to displace the outer memberaxially relative to the nut against the thrust of the strut loadingbefore the nut parts could be relatively hinged out of threadedengagement with the inner member.

The abutment faces of the nut parts may be adapted'to engage with theouter side of the wall of the hollow outer member, in which case each ofthese faces would be disposed at the side of the hinge position of theparts which in an axial sense is opposite to the screw threads on suchparts, the arrangement preventing the said faces hinging inwardlytowards the central axis of the inner member and thus precluding outwarddisplacement of the nut parts away from the screw thread on the innermember.

Alternatively, the abutment faces may engage with the inner side of thewall of the hollow outer member, in which case such faces must in anaxial sense be disposed at the same side of the hinge position as thescrew threads of the severalnut' parts so as again to prevent them frombeing swung outwardly out of threaded engagement with the inner memberwhen the strut is loaded.

Usually the hollow outer member would be in the form of a cylindricaltube but the member may be open along one side thereof if desired, so asto be of channel or opensided tube configuration.

BRIEF DESCRIPTION OF THE DRAWINGS One preferred form of the invention isillustrated in the accompanying drawings wherein:

FIG. l is a side elevation of one form of adjustable strut incorporatingthe invention.

FIG. 2 is a plan view of the nut of the strut depicted in FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENT The adjustable strut illustratedcomprises an outer member 10 in the form of a plain cylindrical tube andan inner member lll having a peripheral screw thread. 12 and one end ofthe inner member ll extends telescopically within the outer member 10.

On the screw threaded part of the inner member I1 is mounted a nut 13which is split along a diametrical axially extending plane into twosimilar parts ll ll each having a screw threaded portion 115 whichextends around rather less than half the circumference of the screwthread 12 so as normally to engage therewith.

The two-nut parts M at positions spaced axially beyond the end of theportions 115 are connected together by aligned hinge pins l6 whichextend through hinge lugs I7 formed on each portion M, the hinge pinsand lugs forming pivot means. The lugs 117 form the extremities ofabutment portions 114 of the parts M and extend beyond the pins 16 onthe side thereof opposite to the screw threaded portions 15 to form aring I8. The portions 15 provide shoulders 1'9 adapted forload-transmitting engagement with the end of the outer member 10 whenthis is within the ring.

The ring l8 has axially extending opposed abutment faces 20, which aredisposed at opposite ends of a diameter extending perpendicular to thehinge axis and which over their entire axially extending length arespaced apart by a distance equal to the outside diameter of the outermember 10 so as to en gage closely with abutment faces lltlll on theouter side of the wall of the member 10 when within the ring.

Insofar as the socket faces 20 extend axially beyond the hinge axis atthe side thereof opposite to the screw threaded portions 15 thearrangement effectively ensures that when the outer member lllll extendswithin the ring so as to be in loadtransmittingengagement throughshoulder l9-withthe nut 13, the two-nut parts 14 are effectivelyheldin'threaded engagement with the screw thread on the inner member ll.I

At the same time when the outer member ill is no longer inload-transmitting engagement with the nut l3, it can be withdrawn fromthe ring 18 thus permitting of the two parts 114 of the nut being swungrelatively apart by grasping the nutrotating handles 21 and swingingthem in an upward direction as viewed in FIG. 1 so as to disengage thethreaded portions BS from the inner member screw threads 12 and permitof the nut 13 being rapidly displaced without rotation, axially of theinner member 111 to some other desired position along the length of theinner member ill in accordance with the desired overall length of thestrut.

One end of each of the two members lltl, ll which are at opposite endsof the strut are respectively provided with upper and lowerload-engaging thrust plates 22, 23 respectively.

lclaim:

ll. An adjustable strut comprising a hollow outer member; an externallythreaded inner member telescopically engaged with the outer memberyand atwo-part nut to transmit load between the members, each part of the nuthaving'an internal, part-screw-thread to engage the external screwthread on the inner member, each such PQTT SCTflW lZI'IICB-Cl notextending around more than half the circumference of the innerconnecting the nut parts for relative pivoting movement of said partsabout a pivot axis transverse to the longitudinal axes of said members,the abutment faces being located about the inner member, and abutmentfaces on said outer member located so that engagement of said faces onthe outer member with said faces on the parts occurs when the strut isunder axial load and causes the part-screw-threads of the nut parts toengage the external screw thread, said nut parts being pivotable aboutsaid pivot axis when the abutment faces are out of engagement todisengage the part-screw-threads from the external screw thread.

1. An adjustable strut comprising a hollow outer member; an externallythreaded inner member telesCopically engaged with the outer member; anda two-part nut to transmit load between the members, each part of thenut having an internal, part-screwthread to engage the external screwthread on the inner member, each such part-screw-thread not extendingaround more than half the circumference of the inner member, and anabutment face, the nut including pivot means connecting the nut partsfor relative pivoting movement of said parts about a pivot axistransverse to the longitudinal axes of said members, the abutment facesbeing located about the inner member, and abutment faces on said outermember located so that engagement of said faces on the outer member withsaid faces on the parts occurs when the strut is under axial load andcauses the part-screw-threads of the nut parts to engage the externalscrew thread, said nut parts being pivotable about said pivot axis whenthe abutment faces are out of engagement to disengage thepart-screw-threads from the external screw thread.
 2. An adjustablestrut according to claim 1 wherein said abutment faces are provided bythe external circumferential surface of the outer member and inwardlydirected faces on the nut parts.
 3. A strut according to claim 2including interengageable load-transmitting faces on the nut parts atone end of the part-screw-threads and one end of the outer member.
 4. Anadjustable strut according to claim 1 including handles on the nut partsoperative to rotate the nut when the part-screw-threads are engaged withthe external screw thread.